below 2550 connected 2950 and 3com switches

[johnleee]

If need to use Vlan X ( x not equal to 1), is the trunk is necessary for 2950 and 3com switches to connect to upper switch 3550? or any other simple / default connection way could work? thanks much!

[jbayuka]

You will need trunking only if you want to transport multiple Vlans over a single link. You could use just use an access port if it is only for a single vlan. You just need associate those connecting ports to that particular port, in your case Vlan X.

HTH